John Gruber illustrates the dangers of not having a clue about history: "The utter simplicity of the iOS home screen is Apple's innovation. It's the simplest, most obvious 'system' ever designed." Thanks for playing.

That's a picture of the control panel of the Newton. This is what the Newton's home screen looked like:

Hold on... as someone who actually owned a Newton Messagepad 120 and used it quite a lot, you are wrong. The NewtonOS had an app drawer where all of your installed apps lived. That is what looks identical to the earliest PalmOS devices. It was a tray with a grid of icons. Yes, the NewtonOS opened in the notepad app (because it was a "notepad", DOH!), but if you wanted to use any other apps installed (and the Newton had a pretty vibrant 3rd party app community at one point), you opened the app drawer and launched them from there. So, yes, the Newton "launcher" looks exactly like the PalmOS home screen. There you go. This doesn't even take in to account that later versions of the NewtonOS didn't even launch the notepad by default and instead showed you the launcher straight away (e.g. eMate 300.)

EDIT: Some could also argue that the way the Newton filtered the apps in to categories was wholesale stolen by Palm for PalmOS 3.0, because PalmOS 2.0 (and prior) sure as hell didn't do that, they instead scrolled (rather awkwardly) the launcher up/down to get to the app you wanted. I also owned (and still do) a Palm Pilot Pro, so I could probably even get pictures, if proof was required. I used to install third party launched on my PP just to be able to manage the mess that the launcher was in.